734 EXPERIMENT STATION RECORD. [Vol.35 



Fiber measurement studies: A comparison of tracheid dimensions in long- 

 leaf pine and Douglas fir, witli data on the strength and length, mean diam- 

 eter and thickness of wall of the tracheids, Eloise Geeby {Ahs. in Science, 

 n. ser., J,3 (1916), No. 1106, p. 360). — This is a progress report on fiber dimension 

 studies as a part of the investigation into the mechanical, physical, and chemi- 

 cal properties of the longleaf pine (Pinus palustris) and Douglas fir {Pseudo- 

 tsuga taxifolia), the work being conducted at the Forest Products Laboratory, 

 United States Department of Agriculture, Madison, Wis. Data were collected 

 from microscopic investigations made at every tenth annual ring on large cross 

 sections from old trees. 



The results obtained show no evidence of a constant fiber length such as 

 was reported by Sanio for the Scots pine. Many more bordered pits were found 

 in the spring than in the summer wood tracheids. The ends of the tracheids 

 were frequently blunt or forked, though they are generally pointed in the 

 summer wood. As a rule, the summer wood tracheids are shorter than the 

 spring wood tracheids in all the material studied. 



A rapid increase in all dimensions was found during the first 20 years of 

 growth. The variation in length in a single tree was found to be from 0.8 to 

 7.65 mm. A direct relation was found to exist in the Douglas fir studied between 

 the thickness of the cell walls of the summer wood and the strength of the 

 material. In young wood, strength of material and thickness of wall were both 

 low. No marked relation was found to exist between width of ring and fiber 

 dimensions, nor was there any decline in the size of the elements due to age 

 of the tree. 



The Douglas fir and pine were not found to differ widely in the dimensions 

 of their elements. Thickness of wall averaged higher in the longleaf pine, but 

 the diameters were somewhat less than in the Douglas fir. 



Permeability and viscosity, W. J. V. Osteehout (Science, n. ser.. 43 (1916), 

 No. 1120, pp. 857-859). — Criticisms are given of the theory of Spaeth that the 

 permeability of the surface layer of protoplasm is determined by its viscosity, 

 which, in turn, depends on its colloidal condition. 



Hail injury to cultivated plants, J. Weigeet (Landw. Jahrb Bayern, S 

 (191S), No. 2, pp. 49-57). — This deals briefly with hail injury to maize, small 

 grains, potatoes, beets, tobacco, vines, and fruit trees, with a few references 

 to related contributions on this subject. 



The injurious effect of tarvia fumes on vegetation, A. H. CnrvTms (Abs. in 

 Science, n. ser., 43 (1916), No. 1106, pp. 363, 364). — An account is given of the 

 destruction of a garden in Hanover, N. H., by fumes of a tar compound used 

 on roads. The injury was found to be due to the constituents of the volatile 

 substances, which condensed in the form of an oily coating on the surfaces of 

 the plants, and did not involve to any extent the passage of gases through the 

 stomata. The amout of injury was found to vary with the distance from the 

 escaping fumes, the temperature of the melting tar, and the age of the plant 

 structures. 



FIELD CROPS. 



Irrigated pastures for northern reclamation projects, F. D. Farrell (TJ. S. 

 Dept. Agr., Bur. Plant Indtis., Irrigated Pastures for Northern Reclamation 

 Projects, 1916, pp. 16, figs. 2). — Based on experiments with irrigated pastures at 

 several field stations and on observations made and information gathered on 

 northern reclamation projects and in some of the other irrigated districts of 

 the same region, directions are presented for the establishment and management 

 of pastures under irrigation. 



